1. Field of the Invention
The present invention relates to rocket motor engines in particular and, more specifically, the invention contemplates a device which prevents the formation in space of large conglomerate masses of debris such as are ejected from solid propellant rocket motors during the several moments immediately following termination of thrust. The invention also contemplates possible other application such as, for example, capturing debris which is contained in the main exhaust nozzle during the operation of thrust reversers, the containment of waste at the main nozzle of any reaction motor, or filtering the exhaust stream of an airborne vehicle.
2. Description of the Prior Art
Many solid propellent rocket motors employ thrust termination devices which consist of exhaust ports built into the vehicle body for the purpose of terminating the forward thrust of the motor after the motor has served its purpose of acceleration. These thrust termination ports are situated such that when they are activated, each allows emission of exhaust in a direction that has a large component opposite the direction of the main thrust of the rocket. Furthermore, these ports are sized and nozzled so that the total thrust of all thrust terminators is equal and opposite to the main thrust of the rocket. The thrust terminators are often activated by detonating explosive charges which open the port covers. Generally, the contaminates which contribute to the problem in tracking rocket motors after thrust termination has occurred will comprise certain solid portions of the exhaust ports as well as the unspent solid propellant. Thus, it is generally the case that when thrust termination devices are operated the material ejected from the rocket motor consists of both so-called hard and soft debris, such as port covers, propellant lining, propellant pieces, and any eroded hardware. Debris thus ejected from the rocket motor has been known to develop into a sizeable particulate cloud many miles in diameter and length when measured in terms of its radar cross section. The disadvantage of formation of clouds of this kind is that they frequently interfere with precise tracking of a missile because tracking stations are not able to clearly distinguish between the rocket motor itself and the particulate cloud formation.
Prior to the present invention, it was known to place porous bags over the exhaust pipes of land-borne motor vehicles to prevent the discharge of unwanted particles into the atmosphere. Furthermore, it was also known to install rigid grills over the exhaust ports of airborne vehicles for the purpose of preventing any untimely discharge into space of some exhaust contaminates. Additionally, vacuum cleaner devices have been designed which force expelled air to be exhausted in a downward direction in order to lessen the amount of weight which is resting on the floor, with a porous debris catcher being installed inside the vacuum cleaner to prevent any dust from being ejected into the atmosphere. These devices, although having some advantage in the particular uses to which they have been applied, are not suitable for application to the ports of rocket motors which have the firing cycle terminated by the initiation of charges which open the thrust termination ports. The novel debris catcher device of the present invention overcomes the difficulties of the prior art and has several additional advantages as will hereinafter be described.